Spinning tool



SPINNING TOOL Filed Nov. 29, 1954 INVENTOR.

HENRY L.TERW1LLIGER ATTORNEYS fto reduce the diameter of the tube at these points.

to expand outwardly into these zones.

United States Paten r r SPINNING TOOL Henry L. Terwilliger, Detroit, Mich, assignor to Calumetand Hecla, Inc., Calumet, Mich., a corporation of Michigan Application November 29,1954, Serial No. 471,605

8 Claims. (Cl. 113-52) The present invention relates to a new method of spinning and a tool for carrying out the improved method. In the past, the necessity ofheating metal tubing to a plastic state during or prior to a spinning operation was recognized. The heating of the tubular-worl piece was carried out by electrical heating, gas heating, or mechanically heating the part by relative rotation between the part and a separate relatively revolving reducing die or a tool having a portion which includes a solid reducing die.

Indeveloping the necessary heat by employing '21 separate reducing die or a portion of 'a die, the preheating is accomplished at the original point or area of reduction as the tube enters the die, and this area of the portion of the die surface has been uninterrupted by reliefs or an open area so that the wheat that point is totally enclosed. As a result, sufiicient heat was obtained by friction to bring the tubing to a plastic state clue to the relative rotation between the tool and tube.

In accordance with the present invention an entirely novel method of bringing the tubing to a temperature sufiicientto provide for satisfactory spinning has been developed. In accordance with'this invention ferrous or non-ferrous tubing 'is brought to proper spinning temperature without employing electrical or gas heating equipment or without employing "a separate'relatively revolving reducing die or a die having a portion totally enclosing the tube at the area of reduction. Instead, the present invention employs a tool including circumferentially spaced blades or members engageable with the tubular work piece, preferably at diametrically opposite zones, leaving continuous openings or relieved spaces in termediate the points of contact in'the zone of original reduction. As a result,relative axial advance between the tool and the tube results in working the tube by the application of pressure at a plurality of zones tending Inasmuch as intermediate the zones of application of pressure, the tubeis completely unconfined, the tube tends As the tube and tool are being relatively rotated, each individual element of the tube in the zone of operation of the tool is mechanically forced or ironed inwardly and is then caused to move outwardly when the application of pressure to such element is terminated. There results a continuous inward and outward movement of elements of the tube, a condition of plastic flow which quickly brings that portion of the tube to the required elevated temperature for satisfactory spinning The heat is due not only to friction between the tube and tool, but moreparticularly, to the continuous plastic fiow imparted to the interior of the tube, with accompanying internal friction.

It is accordingly an object of the present invention toprovide a novel method of preheating a portion of a tube prior to or during the spinning operation which includes applying inward compression to the tube at :circumferentially spaced zones and causing the zone of application of pressure to progress continuously circum 12 for engagement in a driving chuck of any type.

feren'tially around the tube so as to cause individual elements of the tube to be forced alternately inwardly and outwardly.

It is a further object of the present invention to provide a spinning tool including circumferentially spaced portions engageable with the tube which are spaced apart to laeve intervening spaces into which the material of the tube will be forced by the application of pressure.

More specifically, it is an object of the present invention to provide a spinning tool comprising a holder, a plurality of blades disposed in a circular array and spaced apart circumfeientially to provide relief spaces therebetween.

Still more specifically. it is an object of the present invention to provide a tool as described in the preceding paragraph in which the blades are arranged in pairs, and the blades of each pair are disposed diametrically across theaxis of the holder from each other.

It is'a further object of the present invention to provide a tool as described in the preceding paragraphs in which the blades are provided with tube engaging surfaces shaped to reduce the circumferential dimension of the zone of contact between the blades and the tube.

More specifically, it'is an object of the present invention to providea spinning tool as described inthe preceding paragraphs in which the blades are provided with tube engaging surfaces to engage the exterior surface of the tube and in which the tube engaging surfaces are defined by straight elements in a plane perpendicular to theaxis of the tool.

More specifically, it is an object of the present invention to provide a spinning tool as described in the preceding paragraphs in which the blades are provided with tube engagingsurfaces to engage the exterior surface of the tube and in which the tube engaging surfaces are defined by concave elements in a plane perpendicular to the axis of the tool in whichthe radius of concavity of the elements is greater than the radial distance of such surface from the axis of the tool.

Other objects and features of the invention will become apparent as .the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a fragmentary side elevational view showing the arrangement of spinning blades in a holder.

Figure 2 is an end view of the structure shown in Figure 1.

In accordance with the present invention a tool is provided comprising a holder It) having a tapered shank The holder is provided with a plurality of radially disposed inclined slots 14 which receive removable spinning blades 16. The particular means for mounting the blades is not of critical importance but in the presently illustrated embodiment of the invention the holder is provided with a threaded back-up ring 18 engageable with therear ends of the blades and adjustable to feed the blades forwardly after resharpening to maintain size. The diagrammatic illustration of the holder is merely illustrative of the type of holder which may be employed. It will be understood that suitable means (not shown) will be provided to lock the spinning blades in adjusted position.

The blades preferably are formed of rectangular stock and are provided with a spinning end portion or tip indicated at 20 formed of a suitable hard material adapted to withstand high temperatures without injury. A material suitable for such purpose is tungsten carbide. It will be observed that the forward ends of the blades are illustrated as comprising a straight fiat zone 22 which is slightly larger than the initial CD. of the tube on which the spinning operation is to be carried out. A second straight flat zone 24 is provided which corresponds to the CD. of the part of the tube after spinning.

Intermediate the fiat zones 22 and 24 there is an intermediate zone 26 which is concave and which serves to apply inward pressure to the end of the tube as the tube is fed axially into the spinning tool.

For purposes of illustration, a specific example of a satisfactory spinning tool resulted when the zone 22 was located at a distance of /8 from the axis of the holder, and the flat zone 24 was located at a distance of .237" from the axis of the holder. The concave zone 26 was a cylindrical surface having a radius of At the left hand end of this concave zone 26, as illustrated in Figure 1, it was blended into the fiat zone 24 by a convex cylindrical zone having a radius of approximately It will be appreciated that these specific dimensions are given merely to disclose a single embodiment of the invention and are not in any sense to be interpreted as limiting. While four blades are shown in Figure 2, it is found that good results are obtainable with from three to six blades, all equally spaced from each other.

In the illustrated embodiment of the invention the tube engaging surfaces at the ends of the blades 16 are illustrated as composed of straight line elements taken in any section perpendicular to the axis of the holder. As a matter of fact, the surface may be a double concave surface so long as the radius of curvature as measured in planes perpendicular to the axis of the holder, is greater than the distance between the Zone where such curvature appears and the axis of the holder. In other words, when the surface engages the exterior of a tubular work piece, the tube engaging surface of the blade is shaped to minimize the circumferential extent of area of contact of the work piece. Thus, the straight line elements in the illustrated embodiment of the invention may be considered as theoretically tangent at a point to the exterior surface of the work piece. In practice of course, due to deformation and working of the part, the area of contact will be substantial. The width of the blades, as seen in the drawing, is such that the stock moves into engagement with each of said surfaces generally tangentially thereof. As a result the metal of the stock is flexed gradually and gouging by the edges of the blades is avoided. The metal of the stock is thus in extended area contact with the surface of the blades, and its motion has a radial inward component from initial contact up to the center line of the blade.

In operation, as the metal tube is forced to the left as seen in Figure 1 into engagement with the tungsten carbide tips of the blades, pressure is applied to a plurality of circumferentially spaced areas at the end of the tube. Relatively high pressure is permitted due to the use of tungsten carbide and the material of the tube at the area in contact with the blades is forced inwardly of the tube. This inward movement of the material of the tube at circumferentially spaced zones tends to produce outward movement of the material of the tube at the portions thereof intermediate the blades. It Will of course be apparent that the tube and tool have relatively high rotational movement so that there is a continual progressive movement of the area of contact between the blades and tube circumferentially of the tube. Thus, each particular element of the tube is forced inwardly as it passes each individual blade but is thereafter caused to move outwardly as it passes the space intermediate a pair of blades. There is thus a continuous plastic working of the material of the tube which quickly brings the tube up to a high temperature suitable for the final spinning operation. This temperature is due in part to friction between the blades and the end portion of the tube but more particularly, to the plastic back and forth working of the material of the tube.

While the invention has been illustrated as employed to spin the end portion of a tube to a smaller diameter or toa closed condition, it will be appreciated that the invention is not limited to this particular type of spinning and may be employed to enlarge the end of a tube or even to produce a radial or reversely bent flange thereon. A

While the invention may be very simply carried out by employing separate insertable blades in a holder as specifically disclosed herein, it will of course be apparent that the same basic method could be carried out with a single circumferentiallycontinuous reducting die having a tube engaging surface of undulating shape in a crosssection perpendicular to its axis. In such case outward movement of the material of the tube intermediate the zones of application of pressure might be limited as desired and in practice the axial feed could be adjusted to the rate of rotation so that the material of the portion of the tube undergoing heating would be in continuous contact with the undulatory die surface.

The drawings and the foregoing specification constitute a description of the improved spinning tool in such full,

clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A spinning tool comprising means providing a plurality of separate tube engaging surfaces disposed in a circular array and spaced apart circumferentially to provide spaces therebetween into which the material of a tube undergoing spinning may expand, said tubeengaging surfaces defining an inwardly tapered concave recess into which an end of the tube is moved, said surfaces terminating in inner sizing portions spaced apart to spin the tube end to desired size, said tube engaging surfaces being of substantially straight cross-section in planes perpendicular to the axis of said array and of sufiicient width to cause the contact of said stock as it moves into engagement with each of said surfaces to be essentially tangential to thereby cause gradual fiexure of the tube stock as it traverses said surfaces.

2. A tool as defined in claim 1 in which the crosssections of said surfaces in all planes perpendicular to the axis of said array are substantially uniform.

3. A tool as defined in claim 1 in which said tube engaging surfaces are equally spaced.

4. A tool as defined in claim 1 in which said tube engag ng surfaces symmetrically occupy planes which extend radially with respect to the axis of the array.

5. A tool as defined in claim 1 in which the circumferential spacing between outer portions of adjacent tube engaging surfaces is substantially greater than the circumferential extent of the corresponding outer portions of said surfaces, the circumferential spacing between inner portions of said surfaces being substantially less than the circumferential extent of the corresponding inner portions of said surfaces.

6. A tool as defined in claim 1 in which said tube engaging surfaces are formed of a hard sintered material such as tungsten carbide.

7. A tool as defined in claim 1 which comprises a holder, and in which said tube engaging surfaces are formed on independent blades removably carried by said holder.

8. A spinning tool comprising means providing a plurality of separate tube engaging surfaces disposed in a circular array and spaced apart circumferentially to provide spaces therebetween into which the material of a tube undergoing spinning may expand, said tube engaging surfaces defining an inwardly tapered concave recess into which an end of the tube is moved, said surfaces terminating in inner sizing portions spaced apart to spin the tube end to desired size, said tube engaging surfaces being of substantially concave cross-section in planes perpendicular to the axis of said array, the radius of curvature of the concave cross-section being substantially larger than the radius of the spun portion of the tube in contact therewith, said surfaces being of sufficient width to cause the contact of said stock asit 5 moves into engagement with each of said surfaces to be essentially tangential to thereby cause gradual flexure of the tube stock as it traverses said surfaces.

Hesse May 11, 1897 Lauer Mar. 11,- 1941 6 Hill Mar. 9, 1943 Lauer et a1. July 27, 1943 Dewey Sept. 25, 1951 Wright July 6, 1954 Hill Dec. 13, 1955 White Mar. 6, 1956 FOREIGN PATENTS V France Sept; 16, 1953 

